Refrigerant compressor



Jan. 18, 1966 s. A. PARKER 3,229,901

REFRIGERANT COMPRESSOR Filed April 20, 1964 United States Patent 3,229,901 REFRIGERANT COMPRESSOR Sidney A. Parker, Fort Worth, Tex., assignor to Lennox Industries Inc., a corporation of Iowa Filed Apr. 20, 1964, Ser. No. 361,128 9 Claims. (Cl. 230206) This invention relates to a hermetic refrigerant compressor and, more particularly, to an improved compressor having means therein for reducing the oil level in the crankcase during operation below the operating mechanism to reduce the energy losses and thereby reduce the watts input to the compressor motor.

The trend in the refrigeration industry is toward compact refrigerant compressors driven at relatively high speeds. In one type compressor design, the vertically extending crankshaft is journaled in a crankcase resiliently supported in a sealed outer casing, with the drive motor for the crankshaft being located above the compression mechanism in the crankcase.

The hermetic compressor includes a welded shell or outer casing, the lower portion of which defines an oil sump. When the compressor is inoperative, the crankcase is partially submerged in the sump and some oil is within the crankcase above the level of the operating mechanism therein. A relatively large supply of oil is desirable to reduce the adverse effects caused by miscibility of refrigerant and oil. However, it is desirable to remove oil from the crankcase in use or to reduce the oil level below the pistons and flywheel portion on the drive shaft to minimize operational losses due to frictional drag of the drive shaft and parts of the compression mechanism in the oil and to decrease the watts input to the electric drive motor.

In operation of one present compressor design, discharge gas bypasses around the pistons, increasing the pressure within the crankcase. The difference in pressures acting on the oil displaces the oil from within the crankcase. By this construction, there is provided a compact hermetic compressor design, for lubricant is displaced into the annular space defined between an annular sleeve carrying the crankcase and the lower portion of the outer casing.

The above noted compressor design is dependent upon an imperfect mating of a piston and its sealing rings within a cylinder in the compressor block. With modern fabricating equipment and techniques, there need not be very much leakage of gas between a piston and the wall of an associated cylinder. If there were only very little leakage, insuflicient pressure would be built up in the crankcase to force the oil or like lubricant through an opening therein below the level of oil in the sump. Further, under low load conditions, there would be little bypass of discharge gas about the pistons of the compression mechanism and thus, there would be insuflicient pressure in the crankcase to displace lubricant therefrom.

It is desired that oil be removed from within the crankcase during operation in order to minimize interference with the pumping action and to increase the operating efliciency of the electric drive motor.

Further, it is desired to reduce the sound level of the compressor. It has been found that with the twolevel oil sump arrangement, as disclosed for example in Ayling Patent No. 2,963,113, wherein, in operation, oil is stored in the annular space between the annular sleeve carrying the block defining the crankcase .and the lower portion of the outer casing, sound from the compression mechanism is transmitted through the wall of oil to the outside of the compressor.

An object of the present invention is to provide a hermetic refrigerant compression having means for posi- 3,229,901 Patented Jan. 18, 1966 tively reducing the level of lubricant in the crankcase during operation, such means being independent of piston design.

Another object of the present invention is to provide a hermetic refrigerant compressor having a crankcase partially immersed in lubricant in a sump defined in the lower portion of the outer casing when the compression mechanism is inoperative, with pump means for pumping the lubricant from the sump in the compressor during operation into a reservoir disposed above the compression mechanism so as to reduce the level of oil in the crankcase below the operating components therein.

A further object of this invention is to provide a refrigerant compressor of compact design wherein during operation, the lubricant level in the sump is reduced below the level of the flywheel portion of the crankshaft, and wherein an extended annular space, substantially free of lubricant, is provided between the compressor block and the outer casing for reducing the transmission of sound caused by operation of the compression mechanism to the exterior of the compressor. Further objects and advantages of this invention will become more apparent hereafter.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which:

FIGURE 1 is a cross-sectional view of a hermetic refrigerant compressor embodying the present invention; and

FIGURE 2 is a detail view of the upper bearings for the crankshaft and illustrating the U-shaped skived portions in the bearings for feeding oil toward the center of the two upper bearings.

Referring to FIGURE 1, there is illustrated a refrigerant compressor 10 embodying the present invention. The compressor comprises a gas-tight housing including an upper shell 12 and a lower shell 13 integrally joined to one another, as for example, by welding. A plurality of legs 14 may be welded to the lower shell of the com pressor for supporting the compressor in an upright position.

Resiliently supported within the outer housing or casing of the compressor 10 is a compressor block 15 which comprises a motor flange portion 16 and a cylinder crankcase flange portion 17 divided by a partition 18.

Surrounding the lower portion 17 of. the crankcase in spaced relationship to the lower shell 13 of the outer casing is an annular sleeve 20. Formed integrally on the top of the annular sleeve 20 is an out-turned, ringlike flange 21. An annular member 22 having a trans versely disposed lower ring-like flange 23 is aflixed to the lower shell 13. A plurality of resilient spring means 24 are provided between the flange members 21 and 22 for resiliently supporting the crankcase within the outer housing.

Provided within the crankcase 15 are a plurality of cylinders 26. Though a four-cylinder compressor is illustrated, it will be understood by those versed in the art that any desired number of cylinders may be employed. Cylinder sleeves or liners 27 are provided in each of the cylinders 26 and a suitable piston 28 is adapted to reciprocate within each of the cylinder liners 27. Each piston 28 is operatively connected to the eccentric portion 29 of the vertically disposed crankshaft 30, which is journaled in spaced bearings within the crankcase 15. The means for operatively connecting the piston 28 to the crankshaft 30 include a connecting rod 32, which is aflixed at one end to the eccentric portion 29 of crankshaft or drive shaft 30 and at the other end to a wrist pin 34 carried in piston 28.

Closing the end of each cylinder cavity is a valve assembly 36. Such valve assembly may comprise a discharge valve unit 37, a suction valve plate 38 and a suction valve or reed member 39. Each valve assembly is operative in a conventional manner.

The valve assemblies 36 are each held in place in the end of a cylinder by means including a cap 40 retained in position by a Belleville spring 42 and a retaining ring 44.

Provided on the crankcase are a pair of annular circular scaling flanges 48 and 50. These flanges are provided with recesses within which are disposed O-rings 52 and 54 for sealing between the annular sleeve 20 and the respective flanges 48 and 50. Defined between the exterior of the crankcase and the annular shell 20 is a space56 into which discharge gases are passed from the cylinders 26 after compression. The discharge gases pass from the annular chamber 56 through a conduit (not shown) to the conduit 57 for discharge from the compressor to the condenser of the refrigerating system ina known manner. The annular space 56 is provided with a plurality of cavities to impart a muffiingeffect to the discharge .gases which are passed from the cylinders of the compressor to the conduit 57.

Suction gas enters the casing of the compressor via suction line 62. The suction gases pass through a labyrinth or'space 64 defined between flange 23 on sleeve member 22 and flange 21 on sleeve 20 into the top of the outer housing. Then the suction gas passes through opening 67 in the motor cap or end cap 66 affixed to the motor flange portion 16 of the crankcase and down over the electric motor '68, thereby cooling the motor. The suction gas passes through the motor compartment into the suction and discharge valve assemblies 36 via passage means comprising an opening 69 in the partition 18 and an opening 70 in the discharge assembly 37. Thus, it is seen that the interior of the hermetic casing is substantially at suction pressure. p

The motor 68 comprises a stator 72 which is mounted within the motor flange portion 16 of the compressor block or crankcase 15. The stator 72 is inductively connected to the rotor 74 which is aflixed onto the upper portion '76 of the crankshaft 30. The rotor may be connected to the portion 76 of the drive shaft 30 by means of a key 77.

The shaft 30 may be journaled within a lower bearing 80 which is mounted in the lower bearing head 81. The lower bearinghead 81 is maintained in position by a suitable wedge lock spring or retaining spring 82seated within an annular groove in the compressor block 15. Also provided in the lower bearing head 81 is a thrust bearing 83, which has a central opening 84 defined therethrough. Located in the lower portion 85 of the crankshaft 30 adjacent the counterweight portion 86 is a coaxially dis posed hole-87 which constitutes the eye of the impeller or pump means which are defined within the crankshaft 30.

Such pump means may comprise a vertically disposed passageway 90 in shaft 30 which is offset from the axis of rotation of'shaft 30 and is communicated with the eye 87 of the impeller by means of a transversely disposed passage 91. Passage 91' may be open at its ends to lubricate bearing 80. The longitudinally-disposed passage 90 may communicate with a plurality ofports 92, 93, 94 and 95* onthe surface of the eccentric portion 29 of the crankshaft 30'for lubricating the connecting rod bearing surfaces. Also provided in the crankshaft are a pair of transversely disposed passages 97 and 98 for feeding the upper bearing means which journal the crankshaft within the crankcase 15.

The upper bearing means comprise a first bearing 100 and a second bearing 102 which are spaced from one another to define an annular space 103 therebetween and about the crankshaft.

Communicating with the annular space 103 is a passage 104 formed in the partition 18 of the crankcase. The passage 104 communicates with a reservoir 105 defined on the crankcase between the crankcase and an upwardly extended portion of the annular sleeve 20. Passage 104 is also used as venting means for shaft 30. As will be apparent to those persons skilled in the art, the crankshaft may be skived or grooved in the area of the upper hearings to assure proper venting.

Means are provided for returning lubricant from the reservoir 105 to the sump 106 defined in the bottom of the lower shell 13. Such means are dependent upon the design of the compressor and the size of the lubricant particles. As shown, such means may comprise an orifice opening 107 defined in the wall of the annular sleeve 20 and a tube 108 communicated at its upper end with the orifice opening .107 for returning the lubricant to the sump and keeping the lubricant out of the main stream of the upwardly flowing suction gas so as to prevent entrainment of lubricant in the suction gas. If desired, a return passagemay be formed inthe wall of the crankcase. An overflow tube 109 of larger diameter than tube 108 may be provided to communicate with opening 111 for returning oil from reservoir 105 to the sump. It is noted that the tubes 108 and 109 are spaced from the suction gas inlet to the compressor so as to further minimize any entrainment of lubricant particles in the suction gas. An advantage of the illustrated lubricant return means is that the lubricant flowing through tubes 108 and 109 passes in heat exchangerelationship with the suction gas and is cooled thereby.

As aforenoted, it is desirable in present compressor design to utilize as large a supply of oil or lubricant as possible in order to minimize the adverse effects of miscibilty of the oil and refrigerant. When a relatively large supply of oilis utilized in an upright compressor design,

as in the present invention, then the level of oil within the crankcase will create a frictional drag or resistance of the rotating parts of the compression mechanism, thereby adversely effecting the operating efliciency of'the compressor. It is therefore desirable that the level of lubricant in the sump be reduced below the level of the compression mechanism and below the level of the eccentric portion 86 of the drive shaft 30.

In the present invention, this reduction of the oil level in the sump 106 during operation is accomplished by pumping lubricant from the sump through the crankshaft to lubricate the bearings journaling the crankshaft and then directing the pumped lubricant from an annular space 103 defined between the bearings and 102, I

which comprise the upper bearing means, through a passage '104 defined in the partition wall 18 of the crankcase 15 to a reservoir of suflicient size to hold a substantial quantity of oil. The reservoir is sized to hold sufiicient lubricant during operation to reduce the lubricant level below the flywheel portion 86 of shaft 30 and below the lowermost piston 28.

The annular reservoir 105, which is generally U- shaped in cross section, is conveniently defined by an upwardly extended portion of the annular sleeve 20, by flange 48 of crankcase 15 and by an upwardly extending portion of crankcase 15. It will be understood that if desired, the reservoir may be defined solely by a U-shaped or channel-shaped trough defined on the crankcase.

Referring to FIGURE 2, it is seen that the bearing surfaces of the bearings'100 and 102 are provided with U-shaped grooves or skived out portions and 112 for assuring that lubricant fed to the upper bearing means will be directed toward the space 103 between the bearings 100 and 102.

It will be understood that the pump means for displacing lubricant from sump 106 to reservoir 105 may be different from the illustrative pump disclosed. For' example, mechanical pump means may be used.

In the present design, there is a substantial annular refrigerant space defined between the sleeve 20 and the lower shell 13 of the outer housing. It has been found that in certain designs where the level of oil is raised into the space provided between'the annular sleeve 20.

and the lower shell 13 during operation, sound and vibration will be transmitted through the wall and out from the casing. By the present invention, audible vibrations from the compressor are effectively dampened. The sound deadening is further augmented by providing an annular sound deadening ring 114 in frictional engagement with the lower sleeve 13 and by providing an annular sound deadening ring 116 in frictional engagement with the upper shell of the outer casing.

As seen in FIGURE 1, the oil returned from the reservoir 105 to the sump 106 is retained out of the path of the upwardly moving suction gases by tubes 108 and 109 so as to minimize entrainment of the oil in the suction gas. If such entrainment of oil were not minimized, then a film of lubricant might be carried over into the refrigeration system, thereby reducing the heat transfer eificiency of the condenser and the evporator by coating the interior thereof with a film of oil. In certain applications, for example, where lubricant particle size is large and overflow from the reservoir is permitted in an area remote from the suction gas inlet, entrainment of lubricant is not significant and tubes 108 and 109 may be omitted.

By the present invention, there has been provided means for positively displacing lubricant from the crankcase during operation below the level of the compression mechanism and the flywheel portion on the drive shaft. Such means are independent of piston design and load conditions. Pump means formed in the drive shaft are utilized to lubricate the bearings journaling the drive shaft and to pump oil from the sump to a reservoir defined above the compressor block within the outer casing or housing of the compressor. Means are provided for returning the lubricant from the reservoir to the sump. Preferably, the lubricant return path is isolated from the upwardly moving suction gases entering the compressor from the suction line so as to minimize entrainment of lubricant in the suction gas. By the present invention, the watts input to the electric drive motor is reduced. In addition, the present compressor construction effectively supresses noise created within the compressor.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new, and desire to secure by Letters Patent of the United States, is:

1. In a reciprocating compressor, the combination of an outer casing, an annular sleeve within and spaced from said outer casing for forming an annular space therebetween, a compressor block carried in said annular sleeve and defining a crankcase therein, a vertically extending crankshaft journaled in said block, said block defining at least one cylinder and defining a reservoir thereon above said cylinder, a piston reciprocatingly disposed in said cylinder, means operatively connecting said piston to said crankshaft, an electric drive motor carried by the block and being operatively connected to said crankshaft, said block and annular sleeve being partially submerged in lubricant in the sump formed in the lower portion of the outer casing, and longitudinally extending passage means in said crankshaft offset from the axis of rotation for pumping lubricant from the sump into said reservoir on said block during operation, thereby reducing the level of lubricant in the crankcase below the connecting means and piston to increase the operating efliciency of the compressor and reduce the electrical input to the electric drive motor.

2. A reciprocating compressor as in claim 1, wherein said reservoir is constructed and arranged to hold a substantial quantity of lubricant, which lubricant is returned to said sump by passage through said annular space between said annular sleeve and said outer casing, thereby resulting in cooling of the lubricant as it passes in heat exchange relationship with suction gas entering the compressor.

3. In a reciprocating hermetic compressor, the combination of a lower shell and an upper shell interconnected to form a sealed housing, an annular sleeve within said housing and spaced from said lower shell for forming an annular space therebetween, a compressor block cartied in said annular sleeve, a crankcase being defined in said block, a lubricant sump being formed in said lower shell, a vertically disposed drive shaft journaled in bearing means in said block, electric motor means for rotating said drive shaft, cylinder means formed in said block, piston means reciprocatingly disposed in said cylinder means, means operatively connecting said piston means to said drive shaft, said block being partially immersed in lubricant in said sump, pump means in said drive shaft for lubricating said bearing means with lubricant from said sump, reservoir means formed on said block, passage means in said block for communicating said reservoir means with said pump means, whereby in operation, lubricant will be pumped from said sump and crankcase into said reservoir means above the level of the piston means, thereby increasing operating efficiency of the compressor and reducing the power input to the electric motor means.

4. In a refrigerant compressor, an upper shell, a lower shell connected to said upper shell to form a sealed housing, an annular sleeve in said housing spaced from said lower shell to define an annular space therebetween, the lower shell defining a sump for lubricant in the bottom thereof, a compressor block carried in said annular sleeve, means for supporting said compressor block and said annular sleeve in said housing, cylinder means in said compressor block, piston means slidable in said cylinder means, a vertically extending drive shaft journaled in upper and lower bearing means in said block, motor means for rotatively driving said drive shaft, connecting rod means operatively connecting said piston means to said drive shaft, said block and said sleeve cooperating to define a reservoir above said cylinder means, passage means in said block communicating said upper bearing means with said reservoir, and pump means defined by a vertically extending passage in said drive shaft offset from the axis of rotation thereof for lubricating said upper and lower bearing means, whereby in operation, lubricant will be pumped from said sump and temporarily stored in said reservoir, thereby reducing the level of lubricant in said block, and orifice-defining means in said sleeve communicating with said reservoir for returning lubricant from said reservoir to said sump.

5. In a refrigerant compressor, an upper shell, a lower shell connected to said upper shell to form a sealed outer housing, an annular sleeve in said housing and spaced from said lower shell to define an annular space therebetween, the lower shell defining a sump for lubricant, a compressor block defining a crankcase therein carried in said sleeve, the lower portions of said block and said sleeve being partially submerged in said lubricant in said sump, resilient means supporting said compressor block and said sleeve in said housing, at least one cylinder in said block, piston means reciprocatingly disposed in said cylinder, a vertically extending crankshaft journaled in upper and lower bearing means in said block, said crankshaft having a flywheel portion thereon disposed in said crankcase, said upper bearing means comprising a first bearing and a second bearing spaced from one another and defining a space therebetween, electric motor means supported on said block and afiixed to the upper end of said crankshaft for driving same, means operatively connecting said crankshaft to said piston means, said sleeve cooperating with said block to define a reservoir above said cylinder, passage means in said block communicating said space hetween said first and second bearings with said reservoir, pump means in said .crankshaft for lubricating said upper and lower bearing. means, wherebyin operation, lubricant will .be pumped fromsaid sump into said reservoir to reduce the level of lubricant in said crankcase below the flywheel portionof said crankshaft, thereby minimizing frictional drag of'the crankshaft in the lubricant and reducing thepower input to .said electric motor means, and means communicating said reservoir with said sump for returning lubricant thereto.

6. A refrigerant compressor as inclairn wherein said means communicating said reservoir withsaid sumpcomprises anopening in the sleeve adjacent the bottom of the reservoir and a tube aifixed to said sleeve in communication with said opening at its upper end.

7. A refrigerant compressor as in claim 5 wherein said annular space between saidannular sleeve and said lower shell above said sump is substantially oil free in operation and is filled only with suction gas, said annular space functioning as a second deadening chamber to reduce sound transmission from within said block.

8. 'In a refrigerant compressor, an upper shell, a lower shell connected to said upper shell to form a sealed outer housing, an annular sleeve in said housing and spaced from said lower shell to define an annular space therebetween, the lower shelldefining a sump for lubricant, a compressor block defining a crankcase therein carried in said sleeve, the lower portions of said block and said sleeve being partially submerged in said lubricant in said sump, resilient means supporting said compressor block and said sleeve in said housing, at least one cylinder in said block,.piston means slidingly disposed in said cylinder, a vertically extending drive shaft journaled in upper and lower bearing means in said block, said drive shaft having a flywheel portion thereon disposed in said crankcase, said upper bearing means comprising a first bearing and a second bearing spaced from one another and defining a space .therebetween, electric motor means for driving the drive shaft, means operatively connecting said drive shaft to said piston means, said sleeve cooperating with said block to define a reservoir above said cylinder, passage means in said block communicating said space between said first andsecond bearings with said reservoir, pump means in said housing for lubricating said upper and lower bearing means, and for pumping lubricant from said sump to said reservoir to reduce the level of lubricant in said crankcase below the flywheel portion of said crankshaft, thereby minimizing frictional drag of the crankshaft in the lubricant and reducing the power input to said electricmotor means, andmeansfor returning lubricant to said sump.

9. In a reciprocating hermetic compressor, the combination of a lower shell and an upper shell interconnected to form a sealed housing, compression means in-.

cluding a compressor block and an annular sleeve disposed about said block and spaced from said lower shell for forming an annular spa-ce'therebetween, a crankcase being defined in said block, a lubricant sump being formed in said lowershell, a vertically disposed drive shaft jourw naled in bearing means in said block, electric motor means for rotating said drive shaft, cylinder means formed in said block, piston means reciprocatingly disposed in said cylinder means, means operatively connecting said piston means to said drive shaft, said block being partially immersed in lubricant in said sump,pump means in said drive shaft for lubricating said bearing means with lubricant from said sump, reservoir means formed on said block, passage means in said block for communicating said reservoir means with said pump means, whereby in operation, lubricant will be pumped from said sump and crankcase into said reservoir means above the level of the piston means to reduce the level of lubricant in the crankcase, thereby increasing operating eificiency of the compressor and reducing the power input to the electric motor means.

References Cited by the Examiner UNITED STATES PATENTS 6/1956 Borgerd et a1 230-206'X 12/1960 Ayling 230206 X 11/1961 Gerteis 230-206 X 

1. IN A RECIPROCATING COMPRESSOR, THE COMBINATION OF AN OUTER CASING, AN ANNULAR SLEEVE WITHIN AND SPACED FROM SAID OUTER CASING FOR FORMING AN ANNULR SPACE THEREBETWEEN, A COMPRESSOR BLOCK CARRIED IN SAID ANNULAR SLEEVE AND DEFINING A CRANKCASE THEREIN, A VERTICALLY EXTENDING CRANKSHAFT JOURNALED IN SAID BLOCK, SAID BLOCK DEFINING AT LEAST ONE CYLINDER AND DEFINING A RESERVOIR THEREON ABOVE SAID CYLINDER, A PISTON RECIPROCATINGLY DISPOSED IN SAID CYLINDER, MEANS OPERATIVELY CONNECTING SAID PISTON TO SAID CRANKSHAFT, AND ELECTRIC DRIVE MOTOR CARRIED BY THE BLOCK AND BEING OPERATIVELY CONNECTED TO SAID BY THE BLOCK AND ANNULAR SLEEVE BEING PARTIALLY SUBMERGED IN LUBRICANT IN THE SUMP FORMED IN THE LOWER PORTION OF THE OUTER CASING, AND LONGITUDINALLY EXTENDING PASSAGE MEANS IN SAID CRANKSHAFT OFFSET FROM THE AXIS OF ROTATION FOR PUMPING LUBRICANT FROM THE SUMP INTO SAID RESERVOIR ON SAID BLOCK DURING OPERATION, THEREBY REDUCING THE LEVEL OF LUBRICANT IN THE CRANKCASE BELOW THE CONNECTING MEANS AND PISTON TO INCREASE THE OPERATING EFFICIENCY OF THE COMPRESSOR AND REDUCE THE ELECTRICAL INPUT TO THE ELECTRIC DRIVE MOTOR. 